Week Nine: Gene Expression Flashcards
How does genetic information flow in cell?
DNA→RNA→Protein
DNA to RNA (transcription)
RNA to Protein (translation)
What is transcription? Where does it occur in the cell?
A piece of DNA that codes for a specific gene is copied into messenger RNA (mRNA) in the nucleus of the cell
What is translation? Where does it occur in the cell?
Takes place on ribosomes in the cell cytoplasm, where mRNA is read and translated into the string of amino acid chains that make up the synthesized protein
What is a codon, and what is it made of? What do we mean by ‘genetic code’? How many nucleotides are needed to code for one amino acid?
A codon is a DNA or RNA sequence of three nucleotides (a trinucleotide) that forms a unit of genomic information encoding a particular amino acid or signaling the termination of protein synthesis (stop signals). Genetic code refers to the instructions contained in a gene that tell a cell how to make a specific protein. A series of three nucleotides that determine a single amino acid.
What is a transfer RNA? Where are they located in the (eukaryotic) cell? Transfer RNAs bind to two things – what are they? What is the molecular machine that “supervises” that binding?
Transfer RNA (found in the cytoplasm) is a small molecule that transports amino acids to a growing protein during translation. tRNA binds to a specific amino acid on one end and a corresponding mRNA codon on the other. The ribosome supervises the tRNA binding.
What is a mutation and how could it end up changing a protein?
A mutation is a change in the nucleotides sequence of DNA. By changing a gene’s instructions for making a protein, a variant can cause a protein to malfunction or to not be produced at all.
How does the sickle cell hemoglobin trait confer resistance to infection by the malaria parasite? Compare the outcomes for an individual who is homozygous vs heterozygous for the sick cell trait in terms of malaria infection and sickle cell disease.
The sickle cell hemoglobin gets in the way of the parasite infecting the red blood cells. Reducing the number of parasites provides protection against the disease. People who are homozygous have sickle cell anemia disease while those who are heterozygous have sickle trait.
What is the ultimate source of new alleles?
Mutation is the ultimate source of new alleles in plant pathogen populations. It also is the source of new alleles that create new genotypes (such as new pathotypes) within clonal lineages.
What is recombinant DNA and how is it created?
DNA that has been formed artificially by combining constituents from different organisms.
Recombinant DNA technology involves using enzymes and various laboratory techniques to manipulate and isolate DNA segments of interest.
What is a transgenic organism? Give an example of one and the problem it was designed to solve?
Any organism whose genetic material has been altered using genetic engineering techniques. An example of a transgenic organism is insect-resistant corn. This protein prevented ear and kernel diseases while also not infecting the insects surrounding it such as bees, beetles, flies, etc.
Why are scientists interested in producing spider silk? How are scientists mass producing spider silk?
- Create a recombinant gene (a gene that contains parts of different genes that aren’t found together in nature
- combines the yeast regulatory sequence with the spidroin coding sequence - Insert the recombinant gene into living cells
- insert the recombinant gene into a loop of DNA (vector)
- insert the vector into a yeast cell - Produce protein product
- transgenic yeast cultivated under special conditions producer the spidroin protein in large quantities
Why is a vector an important part of creating transgenic organisms?
Transgenic organisms are powerful tools to analyze biological processes or mimic human diseases. A vector acts as a vehicle that transports the gene of interest into a target cell for replication and expression.
